A change in service house design to limit sows contact with boars immediately after weaning may help improve breeding herd productivity, new research has shown.
While weaned sows are generally given partial access to boars to encourage the 'standing response' as an indicator of oestrus, continual contact may not be helpful, since the sows become used to the boars. This can lead to faulty heat detection and therefore inaccurate timing of insemination, says ACMC animal scientist, Lucy Campbell, reporting on research carried out by Behan and Watson.
Segregated service management, in which sows are kept away from the boars for four days after weaning, before being allowed contact, is thought to result in stronger behavioural and physiological responses in the sows.
The research showed that this system enabled insemination to be more closely related to ovulation, resulting in a highly significant increase in farrowing rate and an average litter size increase of more than 0.3 piglets.
The researchers suggested that by avoiding boar stimulation immediately after weaning, sows did not exhaust their supply of essential hormones. In particular, they mentioned the role of oxytoxin - the primary hormone released following olfactory boar stimulation - in causing uterine contractions which aid semen transport.
"It can be seen from this research that ensuring the sow is not stimulated by the boar and thus not releasing oxytoxin until the optimum time for insemination guarantees that the full potential of these hormones is utilised," commented Lucy.
"This highlights the need for housing to be designed to ensure that sows show signs of oestrus at the best period for insemination rather than during the very early stages of oestrus, where insemination may be less fruitful," she added.
